Vetiver oil is a composition extracted from Vetiveria zizanioides (Gramineae), also called Chrysopogon zizanioides. Extracts and modified extracts such as tinctures, concretes, absolutes, essential oils, oleoresins, terpenes, terpene-free fractions, distillates, residues, etc., obtained from Vetiveria zizanioides (Gramineae) are also known (CAS: 84238-29-9; EINECS: 282-490-8). Vetiver oil is also used as a substrate to provide fragrance constituents and compositions such as vetiveria zizanioides extracts (CAS: 84082-84-8; EINECS: 282-031-1), vetiveryl acetate (CAS: 62563-80-8; EINECS: 204-225-7, 263-597-9), vetiverol (CAS: 68129-81-7; EINECS: 268-578-9), vetiverol acetate (CAS: 62563-80-8; EINECS: 263-597-9) and vetiveria Zizanioides (CAS: 8016-96-4; RTECS: YY3180000).
Known vetiveryl esters such as vetiveryl acetate, as used in perfumery and fragrance compositions, are a mixture of products prepared by a chemical reaction between compounds of the vetiver oil with anhydrides, such as the acetylation of alcohol compounds of the vetiver oil with acetic anhydride. Specifically, vetiveryl acetate is generally prepared by industrial acetylation of vetiver oil or vetiverol using acetic anhydride either with or without a catalyst at temperatures up to 120° C., with orthophosphoric acid at room temperature, or with sodium acetate in refluxing toluene followed by distillation, as described by the opinion SCCP/0984/06 of the scientific committee on consumer products of the European commission for health and consumer protection.
Generally, the esterification reaction of vetiver oil is performed in order to modify the olfactory properties of the oil. However, there exists a continuing need to provide vetiveryl esters compositions having more appreciable and subtle set of odor notes. In addition, the stability of known vetiveryl esters is often quite poor. Also, known processes of preparation of known vetiveryl esters need to be improved in regards of sustainability and environment impact. Negative impacts in these processes could be the use of an organic solvent from petrochemistry, the use of additives used in overstoichiometric, stoichiometric or substoichiometric amounts, resulting in many instances in the production of large amounts of waste. For example, acetylation by acetic anhydride is typically performed with this reagent in excess, resulting in the formation of one equivalent or more of acetic acid per ester formed. The energy consumption of these processes is generally high, either to reach the desired reaction temperature or during distillation steps during the work-up. Common processes being based on the use of synthetic carboxylic anhydrides as acylating agents, and common chemicals as additives, the resulting vetiveryl esters are classified as synthetic products.
Accordingly, there exists a continuing need to provide vetiveryl esters with original olfactory properties produced by sustainable processes.